The High Energy Transient Explorer is a small scientific
satellite designed to detect and localize gamma-ray bursts.
The coordinates
of GRBs detected by HETE are distributed to interested ground-based
observers within seconds of burst detection, thereby allowing detailed
observations of the initial phases of GRBs.

The HETE program is an
international collaboration led by
the Center for Space Research at the
Massachussetts Institute of Technology.
Our collaborating institutions include the Institute for Chemistry and
Physics (RIKEN), the Los Alamos National Laboratory
(LANL), the Centre d'Etude Spatiale des Rayonnements (CESR), the
University of Chicago, the University of California, Berkeley,
the University of California, Santa Cruz, the Centre Nationale
d'Etudes Spatiales (CNES), the Ecole Nationale Superieure de
l'Aeronautique et de l'Espace (Sup'Aero),
the Consiglio Nazionale delle Ricerche (CNR),
the Instituto Nacional de Pesquisas Espaciais (INPE), and the
Tata Institute of Fundamental Research (TIFR).

Click
here for information about
the precise pointing direction of the HETE satellite.

(Last update: Mar 28, 2007)

HETE Pointing Information Available

Don't forget that the HETE web page provides
an estimate of the current pointing of the HETE
spacecraft. See the
mission status page for more details; the
data themselves are immediately available on
this page.

Click for more info!

HETE Science

The primary goals of the HETE mission are the
multiwavelength observation of gamma-ray bursts (GRBs) and
the prompt distribution
of precise GRB coordinates to the astronomical community for immediate
follow-up observations. To achieve these goals, the
HETE science payload
consists of one gamma-ray and two X-ray detectors, which,
together, are sensitive to photons in the energy range of
1 keV to ~500 keV. The two X-ray detectors are
coded-aperture imagers, allowing HETE to determine the location
of a GRB to a precision of 10 arc-minutes (typical) to as low
as 10 arc-seconds. Sophisticated on-board processing
software allows the location to be calculated on board in real
time, and ground post-burst analyses will provide refined
localizations

In addition to the study of GRBs, the HETE instruments will
conduct a survey of the X-ray sky. Not only will HETE
be able to detect X-ray sources as faint as a few milliCrab
in a day's observations, but it will be sensitive to any
flares from X-ray sources in the sky.

HETE Operations and Status

On orbit, the HETE spacecraft will always point in the anti-solar
direction
for optimal exposure of the solar panels to the Sun.
As a result, the HETE science instruments monitor a ~2 steradian field
centered roughly on the ecliptic: during the course of a year,
HETE will survey a swatch of sky along the ecliptic which
covers about 60% of the celestial sphere.

Because of the anti-solar orientation of HETE, ground observers will
always know approximately where HETE is observing. In addition, all
bursts detected by HETE will be at least 120 degrees from the
Sun and, therefore, in prime position for observations by
ground-based optical observers.

The scientific instruments
operate during orbit twilight and night, when the Earth is not
blocking their view.

Click for more info!

HETE Burst Alerts

When a GRB is detected by HETE, a summary of the collected
burst data is sent to a series of listen-only ground stations distributed
around the equator. These data are forwarded to MIT, where they are
distributed to ground observers via the GRB Coordinates Network (GCN).
Subscribers to GCN or visitors to the GCN web site can receive notification
of HETE GRB coordinates within seconds of burst onset!

Click to see a movie
of the orbit of HETE over the burst alert stations: